The original idea of a tool for calculating the SQL Server Max Memory comes from Vlad Catrinescu, SharePoint MVP, who wrote a very popular whitepaper SQL Server Performance in a SharePoint Environment:
Despite of the formula (see below) in the whitepaper, Vlad Catrinescu also provided a tool for calculating max memory, a windows forms application that is freely downlodable at sqlmem.codeplex.com
The goal of the SQL Max web app is to take this idea a step further and make it available directly in your browser, on desktop at work, or on the go in your mobile. This mobile web app will also be available for offline access. Simply put, why should you dowload a zip file, extract and run the .exe file? Perhaps you cannot run executable files due restrictions, or perhaps you are not running Windows at all.Check out our contributors!
SQL Max Memory = TotalPhyMem - (NumOfSQLThreads * ThreadStackSize) - (1GB * CEILING(NumOfCores/4)) - OS Reserved
NumOfSQLThreads = 256 + (NumOfProcessors*- 4) * 8 (* If NumOfProcessors > 4, else 0)
ThreadStackSize = 2MB on x64 or 4 MB on 64-bit (IA64)
OS Reserved = 20% of total ram for under if system has 15GB. 12.5% for over 20GB
In Object Explorer, right-click a server and select Properties.
Click the Memory node.
Under Server Memory Options, enter the amount that you want for Minimum server memory and Maximum server memory.
Use the default settings to allow SQL Server to change its memory requirements dynamically based on available system resources. The default setting for min server memory is 0, and the default setting for max server memory is 2147483647 megabytes (MB). The minimum amount of memory you can specify for max server memory is 16 MB.